Electric steam generator



I Feb 10, 1925.

. F. T. KAELIN ELECTRlC swam GENERATOR Filed Sept. 0, 1921 2 Sheets-Sheet 1 Feb, 10, 1925. 1,525,998

F. T. KAELIN ELECTRlC STEAM GENERATOR Filed p 1921 2 Sheets-Shae; 2

Patented Feb. 10, 1925.

PATENT OFFICE.

FREDERICK T. KAELIN. OF MONTREAL. QUEBEC, CANADA.

ELECTRIC STEAM GENERATOR.

Application filed September 10,1921. Serial No. 499,741.

T all whom it may concern.

Be it known that I, Frrnnnron T. KAELIN. V a subjectof the King of Great Britain, and resident of the city of l\-I0ntreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Electric Steam Generators, of which the following is a full, clear, and exact description.

This invention relates to improvements in electric boilers or evaporators and the object of the invention is to provide means Y for evaporating water with a maximum of efficiency by the direct application of electric power.

' At the present time, there is in many localities, especially at night and during summer months, a surplus of electric power. This applies particularly to localities or installations in which it is'impossible to store the surplus water supply of a hydro-electric station in times of light load. If this power, which would otherwise go to waste, can be applied to some useful purpose to replace some other form of energy, it is obvious that an economy has been effected. For example, industrial plants such as dye works. paper and pulp mills, chemical works and many others have need of large quantities of steam. In many cases the amount of steam required is greatly in excess of any waste or exhaust steam from a power plant, so that the steam must be specially generated. If this can be accomplished by the use of otherwise surplus electric power instead of by the consumption 0t fuel, it is obvious that a considerable economy may be effected.

According to the present invention, steam may be produced in large quantities and very economically by the direct application of electric power, the conversion being nearly 100%. The present invention relates particularly to large alternating current in stallations, for example 15,000- kilowatts and over, but it is obvious that it may be used with smaller installations. The invention resides essentially in the provision of submerged electrodes arranged in steamtight boilers, preferably the usual threephase current is employed and three boilers are used connected at the tops and bottoms by equalizing headers for steam and water provided externally of the respectively. An electrode is disposed within each boiler and electrically insulated therefrom, the electrodes being connected severally to the three phases of the circuit and the boilers being electrically connected and grounded. The water in the boilers constitutes a resistance between the electrodes and the boilers and is heated by the passage of current therethrough. By regulating the amount of submergence of the electrodes, that is to say, the amount of resistance in circuit, the amount of current taken can be regulated.

In the drawings which illustrate one embodiment of the invention Fig. l is a front elevation of the apparatus partly in section. a

Fig. 2 is a side elevation.

Fig. 3 is a fragmentary plan view.

Fig. 4 is an enlarged section on the line 4-4, Figure 1. c

Figure 5 is a vertical sectional view of a single boiler illustrating a development of the arrangement shown in Figure 1.

Referring more particularly to the drawlugs, 11 designates a suitable framework supporting the boilers 12. While three boilers are illustrated for use with a three phase circuit, it will be understood that two boilers or only one boiler may be used if desired for two phase and single phase circuits respectively. In the type illustrated, each boiler is provided with an interior shell 13 spaced therefrom but electrically connected with the outer shell of the boiler.

Within the inner shell, there is provided an electrode 14 preferably in the form of a hollow cylinder extending from approximately the top to approximately the bottom of the inner shell 13 but not above or below the inner shell. The electrode is provided preferably at the top with a spider 15 to which is attached a rod 16 serving both to support the electrode and to convey current thereto. This rod passes out of the top of the boiler through aninsulator 17 and is boiler with any suitable terminal 18. The. electrode may be provided with vertically disposed slots 19 at suitable intervals to facilitate the passage of water to and from the interior of the cylindrical electrode. These slots are vertically disposed so as not to interfere a water supply pipe 23 enters from a main 24. The lower ends of the legs are connected by a discharge header '25 in which is located a suitably loaded relief valve '26. by means of which in case of emergency the water may be quickly withdrawn from all boilers. On the opposite side of this relief valve from the boilers. there is provided an adjustable discharge valve 27. which may be similar in construction to the relief valve but which normally operates at a pressure below the pressure for which the relief valve is set. Feed water entering through the pipes 23 is preheated by water in the legs 22. At the upper end of each boiler, a steam outlet pipe is provided carrying a steam safety valve 29ot any suitable type. All the outlet pipes 28 lead to a steam header 30 in which is located a valve 31 of any suitable construction.

In order to minimize as much as possible the use of the boilers themselves as conductors, the inner shells are each electrically connected to a conductor 32, which .is grounded. This connection is preferably established by a plug 33 screwed into the boiler 12 and carrying a cone-headed stud 34, the head of which is securely bedded in the inner shell and the outer end connected to the conductor 32. Nuts 35 on the stud secure the conductor and serve also todraw the cone head of the stud tightly into the shell and the shell tightly against the plug 33. so that a steam-tight ioint is made.

The operation of the device is as follows;- p

1 he electrodes of the several boilers are connected to the three phases of a threephase circuit and water is admitted until the oints 21 of the electrodes are submerged an inch or so. The current is then turned on and a small amount is utilized in heating the water and converting the same to steam. At the same time the inflow of water is reculated. so that the level gradually rises to a predetermined point. say two-thirds of the way up the electrode, at which point the full electric load is taken. The water. which is a conductor between theelectrode and the inner shell of each boiler, acts in the capacity of a resistance, and therefore the greater the submergence of the electrodes the less is the resistance in circuit. The passage of current throughthe water resistance natu rally heats the water and results in the'evolution of steam, which accumulates in the upper part of the boilers until a predetermined pressure, say 100 lbs. is reached. lVhen this pressure is reached, the regulating valve 27 which has been set for 100 lbs, is opened by the downward thrust of the water and allows some water to escape,so that less submergence of the electrodes takes place with a consequent reduction of thecurrent input and of the evolution of steam. The pressure will then drop and the valve :27 will close. lVater is supplied continuously at a calculated rate through the main fl and pipes so that oncethe valve 27 is closedrwater gradually rises about the electrodes and the evolution of steam increases. It will thus be seen that the pressure regulates itself automatically. so as to remain for the most part in the vicinity of the predetermined amount. regardless of the amount of steam delivered through the valve 31 by regulating the level of water in the apparatus. The production of steam varies proportionately to the wetted surface. of the electrodes as does also the consumption of electric power.

The headers QS and 3O ensure the same water levels in all boilers and also the pressures in all boilers. In this way, all three boilers are made to do approximately the same amount of work and no one is underloaded at the expense of over-load in another.

The boilers are so constructed that each presents an absolutely smooth interior surface without any projections. such as rivets. upon which the discharge would localize. The object of the inner shell 13 is to form a terminal or electrode to orfrom which the currentflows. so as to prevent as far as postions may be made to meet with special conditions. In large installations. greater etficiency 1n proportion to the outside dimen- The inner shells 13 may be said to sions of .the apparatus may lie-obtained by .7

providing. as shown in Figure 5. a second grounded electrode 13 disposed concentri cally within the electrode 14. This second groundedelectrode may be merely an upward extension of the pipes 23 and. it such is the case. it will be advisable to provide horizontal or circumferentially disposed slots 36 at different levels within theelectrode 14. so as to permit water to enter at various levels.

The "advantages of the device are manifold. The devicemay be set in operation in a few, minutes and will deliver stea-rniin a much shorter time than would be possible to get up steam in a boiler. The device may bev used as an auxiliary to boilers to supply steam during the night if otherwise waste electric power is available. The device is particularly applicable to high voltages and thus obviates the necessity of a transformer. The resistance element used, namely-water, is about the cheapest thing obtainable, so that there will be no maintenance cost for renewal of the resistance.

Having thus described my invention, what I claim is':

1. In a device of the class described, a series of boilers electrically connected one for each phase of a circuit, and electrodes within said boilers insulated therefrom and connected individually to the phases of the circuit.

2. In a device of the class described, a series of boilers electrically connected, one for each phase of a circuit, anelectrode in each boiler insulated therefrom, said electrodes being connected individually to the phases of the circuit, and means for maintaining water at the same level in all boilers of the series.

3. In a device of the class described, a series of boilers electrically connected, an electrode in each boiler insulated therefrom, means for withdrawing steam from all boilers of the series, and means automatically operable by the steam pressure in the boilers to regulate the water level therein.

4. In a device of the class described. a boiler, an inner shell spaced from said boiler and electrically connected thereto, and an electrode concentrically disposed within said inner shell and insulated therefrom.

5. In a device of the class described, a boiler, an inner shell spaced from said boiler and electrically connected thereto, an electrode concentrically disposed within said inner shell and insulated therefrom, and'automatically operating means for regulating pressure by permitting the level of water in said boiler to adjust itself to the load.

6. A device according to claim 2, in which the electrode is a tube open at both ends.

7. A device according to claim 2, in which the electrode is a tube open at both ends and formed with a series of slots extending substantially parallel with the axis of the tube.

8. A device of the class described comprising a boiler, tubular cylindrical electrodes disposed in the boiler concentrically of one another and of the boiler. and means connecting certain of said electrodes-electrically with the boiler and to ground.

9. A device of the class described co1npris ing a boiler, tubular cylindrical electrodes therein disposed concentric to one another and to the boiler, certain of said electrodes being slotted parallel with the axis and certain of said electrodes being circumferentially slotted, and electricallyconnected with the boiler and to ground.

10. An electric boiler comprising a plurality of closed vesscls,an electrode within each vessel insulated therefrom, each electrode being connected to a separate phase of an al ternating current circuit, and means for regulating steam pressure in said receptacles by governing the electrodes. v

.11. Means for generating steam, which comprises a series-ofmechanically separate but electrically connected vessels, and terminals of an electric circuit disposed one in each vessel and insulated therefrom and at such distances from the walls of thevessels that arcs will notbe formed between the electrodes and vessels, and means for supplying water to and regulating the levelof water in said vessels.

12. In combination with a device accordingto claim 11, means for equalizing steam pressure in said vessels, and means for equalizing water level in the vessels.

'13. In combination with a device according to claim 11, an inner protective shell for each vessel spaced therefrom and electrically connected thereto.

14. A device of the class described comprising a boiler for each phase of an alternating current circuit used, an electrode within and insulated from each boiler and each connected to one'phase of the circuit, said boilers being electrically connected and grounded, and means for regulating steam ressure by governing water level in the oilers.

the extent of submergence of 15.. In combination with a device according to claim 14, an inner shell for each boiler spaced therefrom, and a conductor electrically connecting said inner shells directly to one another and to the round.

16. In a device of t e class described a boiler, a cylindrical electrode dis osed within said boiler, and a cylindrica grounded member encirclin the electrode and disposed concentrical y therewith.

17. In a device of the class described a boiler, a cylindrical electrode disposed within said boiler, and .a. cylindrical grounded member encircling the electrode and dispo'sed concentrically therewith.

18. In a device of the class described, a boiler, an electrode disposed within said boller, and an electrically conductive grounded shell interposed between said boiler and the electrode and adapted to form one termlnal of a path of electric discharge to or from said electrode.

19. In a device of the class described, a 'boiler, a tubular electrode therein insulated therefrom, and a grounded shell within the boiler disposed concentrically of said electrode and encircling the same.

20. A device of the class described, comprising a series of boilers and contained elements according to claim 18 equalin number to the phases of an alternating current circuit, the electrodes being connected severally to the phases of the circuit. 7

21. In a device of the class described, an outer shell adapted to contain liquid, an electrode therein having slots extending in the direction of current flow in the electrode to give communication between opposite sides of the electrode and an inner grounded shell disposed between such electrode and the outer shell to protect the outer shell from destructive electrolytic action.

22.111 a device of the class described, a vessel, an electrode and a ground member therein. said electrode-and member being slotted to provide free communication for a liquid from one side to the other of said electrode and ground member.

23. In a device of the class described, a vessel, a cylindrically curved electrode therein, a grounded member encircling the electrode, and a second grounded member dismasses posed on the opposite side of the electrode from the first grounded member, said grounded members and electrode being dis-- another within the vessel, and a cylindrically curved electrode disposed between said grounded members and arranged concentrically thereof.

25. In a device of the class described, a vessel, a cylindrically curved electrode therein, cylindrically curved members disposed internally and externally of said electrode and concentrically therewith, and ground connections for said internal and external members, said electrode being slotted in the direction of current flow therein, and said internal grounded member being slotted horizontally.-

In witness whereof, I have hereunto set my hand.

FREDERICK T. KAELIN. 

